GHSA-X2X9-GMV2-4R2X
Vulnerability from github – Published: 2026-09-17 18:31 – Updated: 2026-09-18 18:31In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_teql: restore skb->dev on the slave failure path
teql_master_xmit() sets skb->dev = slave before calling the slave's ndo_start_xmit(), but never restores it when that transmit fails. The skb then walks on to the next slave still pointing at the previous one.
If a later slave has no resolved neighbour, teql_resolve() hands the skb to neigh_event_send(), which queues it on that neighbour's arp_queue with the stale skb->dev. skb->dev holds no reference, so deleting the previous slave frees the net_device while the skb is still queued. Whatever runs next on that skb - arp_error_report() on timeout, or neigh_direct_output() -> dev_queue_xmit() once the neighbour resolves - causes a UAF like the one below:
BUG: KASAN: slab-use-after-free in __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) Read of size 4 at addr ffff888106e100b0 by task flood_packet/527 CPU: 0 UID: 0 PID: 527 Comm: flood_packet Not tainted 7.2.0-rc6-g594d90519502 #1 PREEMPT(lazy) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) ? __pfx__raw_spin_lock_irqsave (./include/asm-generic/qrwlock.h:122 (discriminator 4)) ? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) kasan_report (mm/kasan/report.c:595) ? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) __icmp_send (net/ipv4/icmp.c:914 (discriminator 2)) [...] ipv4_link_failure (net/ipv4/route.c:1251 net/ipv4/route.c:1258) ? __pfx_ipv4_link_failure (./include/linux/skbuff.h:4327) ? _raw_write_lock (./include/linux/instrumented.h:55 ./include/linux/atomic/atomic-instrumented.h:1301 ./include/asm-generic/qrwlock.h:98 ./include/linux/rwlock_api_smp.h:230 kernel/locking/spinlock.c:304) ? __pfx__raw_write_lock (kernel/locking/spinlock.c:175) arp_error_report (./include/net/dst.h:438 net/ipv4/arp.c:296) neigh_invalidate (net/core/neighbour.c:1077) neigh_timer_handler (net/core/neighbour.c:1169) [...] Allocated by task 505: kasan_save_stack (mm/kasan/common.c:57) kasan_save_track (mm/kasan/common.c:78) __kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415) __kvmalloc_node_noprof (./include/linux/kasan.h:263 mm/slub.c:5334 mm/slub.c:6905) alloc_netdev_mqs (net/core/dev.c:12055 (discriminator 2)) rtnl_create_link (net/core/rtnetlink.c:3721) rtnl_newlink (net/core/rtnetlink.c:3903 net/core/rtnetlink.c:4044 net/core/rtnetlink.c:4159) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076) [...] Freed by task 536: kasan_save_stack (mm/kasan/common.c:57) kasan_save_track (mm/kasan/common.c:78) kasan_save_free_info (mm/kasan/generic.c:584) __kasan_slab_free (mm/kasan/common.c:253 mm/kasan/common.c:285) kfree (./include/linux/kasan.h:235 mm/slub.c:2677 mm/slub.c:6377 mm/slub.c:6692) device_release (drivers/base/core.c:2636) kobject_put (lib/kobject.c:689 lib/kobject.c:720 ./include/linux/kref.h:65 lib/kobject.c:737) netdev_run_todo (net/core/dev.c:11756) rtnl_dellink (net/core/rtnetlink.c:157 ./include/linux/rtnetlink.h:135 net/core/rtnetlink.c:3651) rtnetlink_rcv_msg (net/core/rtnetlink.c:7076) [...]
Fix this by restoring skb->dev to the master at the end of each slave's iteration.
{
"affected": [],
"aliases": [
"CVE-2026-90071"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-17T17:16:56Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_teql: restore skb-\u003edev on the slave failure path\n\nteql_master_xmit() sets skb-\u003edev = slave before calling the slave\u0027s\nndo_start_xmit(), but never restores it when that transmit fails. The\nskb then walks on to the next slave still pointing at the previous one.\n\nIf a later slave has no resolved neighbour, teql_resolve() hands the skb\nto neigh_event_send(), which queues it on that neighbour\u0027s arp_queue\nwith the stale skb-\u003edev. skb-\u003edev holds no reference, so deleting the\nprevious slave frees the net_device while the skb is still queued.\nWhatever runs next on that skb - arp_error_report() on timeout, or\nneigh_direct_output() -\u003e dev_queue_xmit() once the neighbour resolves -\ncauses a UAF like the one below:\n\nBUG: KASAN: slab-use-after-free in __icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\nRead of size 4 at addr ffff888106e100b0 by task flood_packet/527\nCPU: 0 UID: 0 PID: 527 Comm: flood_packet Not tainted 7.2.0-rc6-g594d90519502 #1 PREEMPT(lazy)\nHardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nCall Trace:\n\u003cIRQ\u003e\ndump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120)\nprint_report (mm/kasan/report.c:378 mm/kasan/report.c:482)\n? __pfx__raw_spin_lock_irqsave (./include/asm-generic/qrwlock.h:122 (discriminator 4))\n? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\nkasan_report (mm/kasan/report.c:595)\n? __icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\n__icmp_send (net/ipv4/icmp.c:914 (discriminator 2))\n[...]\nipv4_link_failure (net/ipv4/route.c:1251 net/ipv4/route.c:1258)\n? __pfx_ipv4_link_failure (./include/linux/skbuff.h:4327)\n? _raw_write_lock (./include/linux/instrumented.h:55 ./include/linux/atomic/atomic-instrumented.h:1301 ./include/asm-generic/qrwlock.h:98 ./include/linux/rwlock_api_smp.h:230 kernel/locking/spinlock.c:304)\n? __pfx__raw_write_lock (kernel/locking/spinlock.c:175)\narp_error_report (./include/net/dst.h:438 net/ipv4/arp.c:296)\nneigh_invalidate (net/core/neighbour.c:1077)\nneigh_timer_handler (net/core/neighbour.c:1169)\n[...]\nAllocated by task 505:\nkasan_save_stack (mm/kasan/common.c:57)\nkasan_save_track (mm/kasan/common.c:78)\n__kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415)\n__kvmalloc_node_noprof (./include/linux/kasan.h:263 mm/slub.c:5334 mm/slub.c:6905)\nalloc_netdev_mqs (net/core/dev.c:12055 (discriminator 2))\nrtnl_create_link (net/core/rtnetlink.c:3721)\nrtnl_newlink (net/core/rtnetlink.c:3903 net/core/rtnetlink.c:4044 net/core/rtnetlink.c:4159)\nrtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n[...]\nFreed by task 536:\nkasan_save_stack (mm/kasan/common.c:57)\nkasan_save_track (mm/kasan/common.c:78)\nkasan_save_free_info (mm/kasan/generic.c:584)\n__kasan_slab_free (mm/kasan/common.c:253 mm/kasan/common.c:285)\nkfree (./include/linux/kasan.h:235 mm/slub.c:2677 mm/slub.c:6377 mm/slub.c:6692)\ndevice_release (drivers/base/core.c:2636)\nkobject_put (lib/kobject.c:689 lib/kobject.c:720 ./include/linux/kref.h:65 lib/kobject.c:737)\nnetdev_run_todo (net/core/dev.c:11756)\nrtnl_dellink (net/core/rtnetlink.c:157 ./include/linux/rtnetlink.h:135 net/core/rtnetlink.c:3651)\nrtnetlink_rcv_msg (net/core/rtnetlink.c:7076)\n[...]\n\nFix this by restoring skb-\u003edev to the master at the end of each slave\u0027s\niteration.",
"id": "GHSA-x2x9-gmv2-4r2x",
"modified": "2026-09-18T18:31:26Z",
"published": "2026-09-17T18:31:49Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90071"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/00d8a387b23b7831ad9919256a6b9caaa10f19c3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/012559cf3c67ce8825a31d4f66b040b6fbaf775e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0cd75037948567193f7f5767176538822ce23873"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1360bc93f5be1be3cf937ebea667b3418dd30a79"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/96bc345a3f17543d0d92ada609e02198d6380e26"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/aa39a790d56b40bfcf3861653ceb46a3a113adb6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d453bf439ef230b5743afc25e194adacca8c6e43"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dc4b95b8fee95113587e93ca116356032d271371"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.